Today’s big celestial show was supposed to be the 150-foot wide asteroid 2012 DA14, closing within a razor thin margin of Earth, but passing safely (at 2:24 p.m. ET). But a very large meteor or “fireball” stole its thunder, violently blowing up as it entered the atmosphere over central Russia, producing a shockwave that shattered windows, rocked buildings, and injured hundreds.
Compilation of videos of fireball streaking through atmosphere
A fragment of the meteor is believed to have dug a large crater about 20 feet wide (according to the BBC).
The meteor streaked through the sky over Chelyabinsk, which is located just over 900 miles east of Moscow near the Ural mountains.
Phil Plait, author of the popular “Bad Astronomy” blog, said the proximity in the timing of the fireball - which struck around 9:20 a.m. local time - and the asteroid was likely just a coincidence.
“I do not think this is related in any way to the asteroid 2102 DA14!”, Plait wrote. “For one thing, this occurred about 16 hours before DA14 passes. At 8 kilometers per second that’s nearly half a million kilometers away from DA14. That puts it on a totally different orbit.”
The meteor was orders of magnitude larger than the typical 1 millimeter size of those which enter the atmosphere. Consider this description from the Russian Academy of Sciences (via the Radio Free Europe live blog):
The object was “a few meters” [approximately 10 feet] across, but weighed around 10 tons and had a total energy of “a few kilotons.” It entered the atmosphere at a speed of 15-20 km/second [roughly 30-45 thousand miles per hour] and broke up an altitude of 30-50 kilometers [18 to30 miles] .
Wunderground’s Jeff Masters noted meteors this big enter Earth’s atmosphere about every 5 years, but that the impact of this particular meteor on humans is “unprecedented” in modern times. A news article in the journal Nature says it’s the biggest recorded object to hit Earth in a century.
Both because most of the Earth’s land area is not densely populated and oceans cover such a large area, most inbound space material is not observed and eludes human impact.
Fireballs - not typically this big - regularly race through the Earth’s atmosphere, but daytime sightings are quite rare. Only two daylight fireballs are sighted per year on average according to the American Meteor Society, which offers this additional detail on the phenomena:
Fireballs occur every day over all parts of the Earth. It is rare though for an individual to see more than one or two per lifetime as they can also occur during the day (when the blinding sun can obscure them), or on a cloudy night, or over the ocean where there is no one to witness them. Observing during one of the major annual meteor showers can increase your chance of seeing another bright meteor.
The Russian meteor’s impact underscores the risk posed by thousands upon thousands of unknown objects zipping through space.
Related: Asteroid’s pass near Earth a close call in cosmic terms only (Joel Achenbach, Washington Post)
“This is definitely a wake up call to the surprises possible in the cosmic shooting gallery within which the Earth exists,” said Capital Weather Gang’s Steve Tracton, who wrote yesterday’s blog post on asteroid 2012 DA14 and the threat of asteroids and other space rocks - large and small - on our planet.
Correction (10:30 a.m.): For a few minutes after this post was published, it contained a video said to show a crater from a fragment of the meteor. The video was not of the crater and has been removed.